Radio → RF Test


Setup


E-DBA

Sets the GeminiG3 to its normal operating mode. The base channel may change as the mobile roams to a new base

Test Mode

This mode is used to select the radio channel to be used for test transmissions. Placing the GeminiG3 in test mode suspends roaming function.

Roam

The Roam button forces the mobile to roam to all enabled channels when in E-DBA mode. The unit will switch to the channel with the best "Last RSSI". Button is inactive in Test Mode.

Scan

The Scan button forces the unit to scan all channels with valid frequencies (enabled or not) and update the last RSSI column. Button is inactive in E-DBA mode.

Base Channel

This read-only field displays the radio channel number against a white square on a blue background. It indicates the base station to which the mobile is currently registered.

To set frequency, see the Setup (Advanced) → RF (Freq.) section

Active Channel

These read-only fields display the active RX and TX radio frequencies (in MHz) against a yellow rectangle on a blue background. It indicates the current frequencies the radio is on.

Other frequency indicating fields (not against yellow rectangles) show what and how many frequencies the base has approval to use.

If the active channel indications do not correspond to the base channel, it indicates either that roaming is in progress or that testing activity is taking place.

To set frequency, see the Setup (Advanced) → RF (Freq.) section.

Enable

Select as many non zero-frequency channels as desired for Roam option.
Vertical scroll to see the fields for all 32 frequencies.

Last RSSI

Shows the last RSSI information obtained on that channel. Information may be out-of-date if the mobile has been on a single channel for a long time.

GoTo

Available in Test Mode only. Forces the unit to the specified channel (enabled or not).

Enable All

Selects all non-zero frequency fields

Disable All

Deselects all non-zero frequency fields

Apply

Activates the "Enable All" or "Disable All" selection


RSSI


RSSI Table

Main Raw = Raw dBm value from main radio receiver

Main Cal = Calibrated dBm value from main receiver DSP

Diversity Raw = Diversity raw dBm value from diversity radio

Diversity Cal = Calibrated dBm value from diversity receiver DSP.

Range

-120 to -40 dBm

Thresholds

-90 to -60 dBm


Test Tone

Select the desired test tone, press the "Execute" button to transmit a test signal on the channel selected for 20 seconds or until the "Cancel current test" button is pressed.

The functions of all the other buttons are inoperative during test transmissions.

Modulated

Test transmission generates a carrier modulated with a test tone to check deviations. For specific test tone and/or deviation values, see the relevant table in the Gemini G3 User manual.

Unmodulated

Test tone is an unmodulated carrier that gives a clear carrier and used for checking:

Power check:

Connect an in-line power meter between the radio and the antenna.

Measure the forward (nominal 27W) and reflected power levels by pressing the Execute button. Never exceed 1W of reflected power.

100 Hz square wave

Starts a test transmission of a carrier modulated by a square wave. Used to check low-frequency balance at a frequency of 100 Hz

Random Data

Starts a test transmission of a 20 seconds modulated carrier with random data

Random data test transmission is not usually required.
If low system performance is noticed, System Engineering may request the user to run this Random Data test for checking low-frequency balance and maximum deviation over data.

Random data test requires the use of an IFR COM-120B service monitor with option 03= 30KHz IF filter and its DC coupled demodulator output selected.


Back to Top